Flow channeling in a single fracture induced by shear displacement

• Published in: Geothermics 2006-10, Vol.35 (5), p.576-588
• Main Authors: Auradou, Harold, Drazer, German, Boschan, Alejandro, Hulin, Jean-Pierre, Koplik, Joel
• Format: Article
• Language: English
• Subjects: Dispersion; Earth Sciences; Fluid Dynamics; Fractal; Fracture; Hot dry rock; Hydrodynamic; Meteorology; Mixing; Permeability; Physics; Sciences of the Universe; Self-affine
• ISSN: 0375-6505; 1879-3576
• DOI: 10.1016/j.geothermics.2006.11.004

The effect on the transport properties of a fracture of a shear displacement u → between its complementary surfaces is investigated experimentally and numerically. The shear displacement u → induces an anisotropy of the fracture aperture field with a correlation length scaling of | u → | , which is significantly larger in the direction perpendicular to u → . This reflects the presence of long fluid flow channels perpendicular to the shear displacement, resulting in a higher effective permeability in that direction. Such channels will have a strong influence on the transport characteristics of a fracture, such as, for instance, its thermal exchange area, crucial for geothermal applications. Miscible displacement fronts in shear-displaced fractures obtained experimentally display a self-affine geometry with a characteristic exponent directly related to that of the fracture surfaces. We present a simple model, based on the channeling of the aperture field, which reproduces the front geometry when the mean flow is parallel to the channels created by the shear displacement.